GeoNet reported that the Mud Rift feature at Okataina's Waimangu Geothermal area erupted during 17-20 May, the first time since 1989. The Mud Rift geothermal vent formed in 1906 in the Raupo Pond Crater (one of multiple craters which formed in June 1886) and is 36 m long, 5-6 m wide, and 15 m deep. The steam-driven events mostly ejected fine sand and mud, and there was abundant evidence of fluids flooding into the rift, especially at the W end. Nearby vegetation was brown, and there was some evidence of collapse around the edges of the vents.

A short but intense sequence of earthquakes occurred in the Lake Rotomahana area of the [Tarawera] rift on 16 November. The largest event (ML 3.8) occurred at 1835, in the middle of the sequence; events continued until about 2000. A geodetic survey of the Lake Rotomahana strain monitoring pattern was completed ~20 minutes before the earthquake sequence commenced. Selected stations were reoccupied three days later but no significant co-seismic deformation was detected. All the earthquakes appeared to be of tectonic origin. Similar swarms were recorded 22-23 February 1986 and in February 1983.

The 17-km-long Tarawera Rift was the site of a vigorous eruption in 1886 that ejected ~0.7 km3 of basaltic magma in ~4 hours (Nairn and others, 1986); large phreatic explosions occurred from Lake Rotomahana, which has grown substantially since that eruption. Phreatic explosions have been recorded [16] times between 1896 and 1973 in the [Waimangu] thermal area to the SW, along the rift.

Weekly Reports - Index

GeoNet reported that the Mud Rift feature at Okataina's Waimangu Geothermal area erupted during 17-20 May, the first time since 1989. The Mud Rift geothermal vent formed in 1906 in the Raupo Pond Crater (one of multiple craters which formed in June 1886) and is 36 m long, 5-6 m wide, and 15 m deep. The steam-driven events mostly ejected fine sand and mud, and there was abundant evidence of fluids flooding into the rift, especially at the W end. Nearby vegetation was brown, and there was some evidence of collapse around the edges of the vents.

Information is preliminary and subject to change. All times are local (unless otherwise noted)

A series of shallow earthquakes occurred 23-29 September a few kilometers SE of Haroharo Dome, in the Okataina Volcanic Center (figure 1). The main earthquake was at 1423 on 23 September. A foreshock preceded it by about 3 minutes, and three of the four large aftershocks followed at 1429, 1440, and 1452 (table 1). Many other aftershocks were recorded, the last at 0530 on 29 September.

Figure 1. Map showing the Haroharo Volcanic Complex and part of the Tarawera Volcano in the Okataina Volcanic Center. From Cole and Nairn (1975).

Table 1. Earthquakes of M > 2.5 recorded in the Okataina Volcanic Center during 23-29 September 1982.

Date

Time

Magnitude

23 Sep 1982

1420

[3.3]

23 Sep 1982

1423

4.1

23 Sep 1982

1429

2.6

23 Sep 1982

1440

3.2

23 Sep 1982

1452

[2.9]

27 Sep 1982

1806

[2.7]

I.A. Nairn, working on the N side of Tarawera Volcano (~11 km S of the epicenters) on 23 September, felt shocks and heard rockfalls nearby. He estimated the Modified Mercalli intensities of the foreshock and main shock as IV, and of the aftershocks at 1440 and 1452 at III-IV. He described the ground vibrations as low-frequency but relatively large-amplitude. Other nearby NZGS personnel noted the relatively low frequency of the felt shocks compared to typical local felt earthquakes. Observers noted that although they did not feel the shocks strongly outdoors, houses and vehicles resonated to large-amplitude vibrations. A small seiche was recorded on the N side of Lake Tarawera (7-8 km SW of the events). Three tilt networks around Tarawera Volcano showed no significant changes.

J.H. Latter placed the hypocenter for the 27 September event [at 38.129°S, 176.531°E, figure 1] about 5 km SE of Haroharo Dome at a depth of about 2 km. Nairn reported that this location coincides with a small area of surface faulting and geothermal activity. The 23 September earthquakes could not be located because of the lack of any nearby seismic records, but epicenters were estimated to be within 6 km of the 27 September event. Latter noted that the slow propagation of energy from the earthquakes and the low frequency of the felt shocks might suggest that they were "roof rock" events generated by activity in an underlying magma body. However, no volcanic tremor was detected during or after the earthquake sequence.

Although Haroharo has not been historically active, five eruptions in the last 10,000 years have been dated by 14C or tephrochronological methods. Very large explosive eruptions occurred roughly 2,050, 2,850, 5,050, and 7,050 years before the present (BP). Dome extrusion occurred at 2,450 years BP (± 400 years).

[Reference. Cole, J.W., and Nairn, I.A., 1975, Catalog of active volcanoes of the world, part XXII.]

A short but intense sequence of earthquakes occurred in the Lake Rotomahana area of the [Tarawera] rift on 16 November. The largest event (ML 3.8) occurred at 1835, in the middle of the sequence; events continued until about 2000. A geodetic survey of the Lake Rotomahana strain monitoring pattern was completed ~20 minutes before the earthquake sequence commenced. Selected stations were reoccupied three days later but no significant co-seismic deformation was detected. All the earthquakes appeared to be of tectonic origin. Similar swarms were recorded 22-23 February 1986 and in February 1983.

The 17-km-long Tarawera Rift was the site of a vigorous eruption in 1886 that ejected ~0.7 km3 of basaltic magma in ~4 hours (Nairn and others, 1986); large phreatic explosions occurred from Lake Rotomahana, which has grown substantially since that eruption. Phreatic explosions have been recorded [16] times between 1896 and 1973 in the [Waimangu] thermal area to the SW, along the rift.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Maungakakaramea
Rainbow Mountain

Cone

743 m

38° 19' 0" S

176° 23' 0" E

Maungaongaonga

Cone

826 m

38° 20' 0" S

176° 21' 0" E

Onepu

Cone

189 m

38° 4' 0" S

176° 43' 0" E

Rerewhakaaitu

Tuff cone

38° 16' 0" S

176° 30' 0" E

Rotorua

Vent

Tuahu

Tuff cone

790 m

38° 7' 0" S

176° 28' 0" E

Craters

Feature Name

Feature Type

Elevation

Latitude

Longitude

Awaatua Bay

Crater

438 m

38° 17' 0" S

176° 30' 0" E

Haroharo

Fissure vent

914 m

38° 5' 31" S

176° 30' 29" E

Rerewhakaaitu

Fissure vent

438 m

38° 17' 0" S

176° 30' 0" E

Rotoatua, Lake

Crater

38° 4' 0" S

176° 25' 0" E

Rotoiti

Pleistocene caldera

Rotokawau, Lake

Maar

38° 4' 0" S

176° 23' 0" E

Rotoma

Pleistocene caldera

38° 3' 0" S

176° 35' 0" E

Tarawera

Fissure vent

1111 m

38° 14' 0" S

176° 30' 0" E

Te Whekau

Crater

38° 10' 0" S

176° 23' 0" E

Wahanga-Waimangu
Chasm, The

Fissure vent

1111 m

38° 14' 0" S

176° 30' 0" E

Domes

Feature Name

Feature Type

Elevation

Latitude

Longitude

Crater Dome

Dome

38° 14' 0" S

176° 30' 0" E

Eastern Dome

Dome

518 m

38° 13' 0" S

176° 34' 0" E

Edgecumbe, Mount

Dome

821 m

38° 6' 0" S

176° 44' 0" E

Green Lake Plug

Dome

366 m

38° 15' 0" S

176° 28' 0" E

Hainini

Dome

38° 8' 0" S

176° 29' 0" E

Kanakana
Plateau Dome

Dome

945 m

38° 14' 0" S

176° 31' 0" E

Makatiti

Dome

914 m

38° 9' 0" S

176° 28' 0" E

Mangawhakamana

Dome

728 m

38° 8' 0" S

176° 35' 0" E

Matahawra

Dome

550 m

38° 2' 0" S

176° 29' 0" E

Pararoa

Dome

525 m

38° 4' 0" S

176° 34' 0" E

Parewhaiti

Dome

700 m

38° 7' 0" S

176° 30' 0" E

Puhipuhi

Dome

335 m

38° 11' 0" S

176° 36' 0" E

Pukepoto

Dome

686 m

38° 9' 0" S

176° 21' 0" E

Ridge Dome
Waiwhakapa

Dome

830 m

38° 15' 0" S

176° 32' 0" E

Rotokakahi

Dome

680 m

38° 13' 0" S

176° 21' 0" E

Rotokohu

Dome

38° 6' 0" S

176° 31' 0" E

Rotomahana

Dome

38° 15' 0" S

176° 29' 0" E

Ruawahia

Dome

1111 m

38° 14' 0" S

176° 30' 0" E

Southern Dome
Koa

Dome

1024 m

38° 15' 0" S

176° 30' 0" E

Tapahoro

Dome

914 m

38° 8' 0" S

176° 29' 0" E

Te Hapeotoroa

Dome

577 m

38° 17' 0" S

176° 25' 0" E

Te Horoa

Dome

38° 10' 0" S

176° 25' 0" E

Te Kumete

Dome

544 m

38° 15' 0" S

176° 25' 0" E

Tikorangi

Dome

550 m

38° 4' 0" S

176° 33' 0" E

Tutaeheka

Dome

719 m

38° 15' 0" S

176° 21' 0" E

Wahanga

Dome

975 m

38° 13' 0" S

176° 31' 0" E

Western Dome

Dome

38° 15' 0" S

176° 28' 0" E

Whakapoungakau

Dome

759 m

38° 6' 0" S

176° 24' 0" E

Thermal

Feature Name

Feature Type

Elevation

Latitude

Longitude

Kawerau

Thermal

60 m

38° 3' 0" S

176° 43' 0" E

Onepu Springs

Hot Spring

60 m

38° 3' 0" S

176° 43' 0" E

Otei Springs

Hot Spring

319 m

38° 3' 0" S

176° 34' 0" E

Paukohurea

Thermal

400 m

38° 19' 0" S

176° 19' 0" E

Rotoma Geothermal Field
Rotoehu, Lake

Thermal

305 m

38° 2' 0" S

176° 33' 0" E

Rotomahana

Thermal

335 m

38° 17' 0" S

176° 25' 0" E

Te Haehaenga

Thermal

Te Kopia

Thermal

610 m

38° 24' 29" S

176° 14' 0" E

Waikite

Thermal

400 m

38° 19' 0" S

176° 19' 0" E

Waimangu

Thermal

468 m

38° 17' 0" S

176° 23' 0" E

Waitangi Soda Springs

Hot Spring

305 m

38° 2' 0" S

176° 33' 0" E

Basic Data

Volcano Number

Last Known Eruption

Elevation

LatitudeLongitude

241050

1981 CE

1111 m / 3645 ft

38.12°S
176.5°E

Volcano Types

Lava dome(s) Caldera(s) Fissure vent(s)

Rock Types

MajorRhyolite

MinorBasalt / Picro-BasaltDaciteAndesite / Basaltic Andesite

Tectonic Setting

Subduction zoneContinental crust (> 25 km)

Population

Within 5 kmWithin 10 kmWithin 30 kmWithin 100 km

18
579
79,591
362,413

Geological Summary

The massive, dominantly rhyolitic Okataina Volcanic Centre is surrounded by extensive ignimbrite and pyroclastic sheets produced during multiple caldera-forming eruptions. Numerous lava domes and craters erupted from two subparallel NE-SW-trending vent lineations form the Haroharo and Tarawera volcanic complexes. Lava domes of the Haroharo complex, at the northern end of the Okataina Volcanic Centre, occupy part of the 16 x 26 km Pleistocene Haroharo caldera, which formed incrementally between 300,000 and 50,000 years before present (BP). The oldest exposed rocks on the caldera floor are about 22,000 years old. The Tarawera complex at the southern end of Okataina consists of 11 rhyolitic lava domes and associated lava flows. The oldest domes were formed as late as about 15,000 years BP, and the youngest were formed in the Kaharoa eruption about 800 years BP. The NE-SW Tarawera vent lineation extends from the two dacitic cones of Maungaongaonga and Mangakakaramea on the SW to Mount Edgecumbe on the NE. Construction of the Haroharo and Tarawera complexes impounded lakes Rotoiti, Totoehu, Okataina, and Tarawera against the outer margins of the Okataina ring structure. A major hydrothermal area is located at Waimangu; the world-renowned Pink and White Terrace siliceous sinter deposits were destroyed during the major basaltic explosive eruption of 1886.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Emission History

There is no Emissions History data available for Okataina.

Photo Gallery

The Haroharo volcanic complex is the NW-most of two lava dome complexes forming the Okataina volcanic centre. A 16 x 28 km wide caldera was formed incrementally during eruptions between 300,000 and 50,000 years ago. Its rim, seen in this photo in the background across an infilling caldera lake, is generally obscured by a group of overlying lava domes. All post-caldera domes are less than 20,000 years old, and the most recent Haroharo eruption took place about 3500 years ago.

Photo by Ian Nairn (Geological Survey of New Zealand).

The 1886 Tarawera eruptive fissure, seen from the north, cut lava domes of the 800-year-old Kaharoa eruption. The rocks of the 1886 eruption, 20-30 m thick here, are red and black, and overlie white rhyolitic pyroclastic rocks of the Kaharoa eruption. This view shows a 2-km-long section of the 8-km en echelon fissure with gray rocks of the Ruawahia lava dome appearing at the far end.

Photo by Bruce Houghton (Wairakei Research Center).

The SE part of the fissure within Ruawahia crater reveals stratigraphy from the ca. 700 BP Kaharoa and 1886 CE eruptions. The 35-m-thick light-colored Kaharoa plinian deposits at the base are largely obscured by talus fans of scoria from above. The thick overlying bright red scoria is from phase 2 of the 1886 eruption. Above it is a thin black zone (phase 3) consisting of very widespread scoria fall. Phase 4 (at the top) consists of white rhyolitic blocks ripped off the walls during the vent widening in the last half hour of the 10 June 1886 eruption.

Photo by Bruce Houghton (Wairakei Research Center).

The flat-topped Tarawera lava dome complex at the top of the photo to the NE is one of two large dome complexes forming the Okataina volcanic center at the northern end of the Taupo volcanic zone. An eruptive fissure that cuts the dome complex and extends across Lake Rotomahana to the foreground was the source of a major eruption in 1886. The Tarawera complex and the Haroharo complex off the photo to the left were both sources of major explosive eruptions during the Pleistocene and Holocene that produced large ignimbrite sheets.

The 800-year-old Kaharoa eruption was the first Holocene eruption of the Tarawera lava dome complex. It produced an extensive rhyolitic airfall deposit that extended to the east coast of North Island. Geologist Pat Brown examines a charcoalized log within a pyroclastic-flow deposit from this eruption. The upper part of the section consists of blocky debris from collapse of a rhyolitic lava dome at the end of the eruption.

Photo by Jim Cole (University of Canterbury).

The steaming Waimangu cauldron is located near the southern end of the 1886 eruptive fissure. Intermittent phreatic eruptions took place from this and other craters south of Lake Rotomahana from 1886 until as recently as 1973. Waimangu (black water) geyser was spectacularly active from 1900 until it became extinct on November 1, 1904.

Photo by Richard Waitt, 1986 (U.S. Geological Survey).

This large fissure system produced during a major explosive eruption at Tarawera in 1886 is one of the most dramatic features of the massive Okataina Volcanic Centre. Okataina is surrounded by extensive ignimbrite and pyroclastic sheets produced during caldera-forming eruptions. The subparallel NE-SW-trending Haroharo and Tarawera complexes consist of rhyolitic lava domes and associated lava flows that formed between about 15,000 and 800 years ago and impounded lakes against the margins of the Okataina ring structure.

Photo by Richard Waitt, 1986 (U.S. Geological Survey).

GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Affiliated Sites

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the MAGA Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

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